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• aaccoder : add a new perceptual noise substitution implementation

  2 juillet 2015, par Rostislav Pehlivanov

  aaccoder : add a new perceptual noise substitution implementation
  This commit finalizes the PNS implementation previously added to the encoder
  
  by moving it to a seperate function search_for_pns() and thus making it
  
  coder-generic. This new implementation makes use of the spread field of
  
  the psy bands and the lambda quality feedback paremeter. The spread of the
  
  spectrum in a band prevents PNS from being used excessively and thus preserve
  
  more phase information in high frequencies.  The lambda parameter allows
  
  the number of PNS-marked bands to vary based on the lambda parameter and the
  
  amount of bits available, making better choices on which bands are to be marked
  
  as noise. Comparisons with the previous PNS implementation can be found
  
  here : https://trac.ffmpeg.org/attachment/wiki/Encode/AAC/
  This is V2 of the patch, the changes from the previous version being that this
  
  version uses the new band->spread metric from aacpsy and normalizes the
  
  energy using the group size. These changes were suggested by Claudio Freire
  
  on the mailing list. Another change is the use of lambda to alter the
  
  frequency threshold. This change makes the actual threshold frequencies
  
  vary between +-2Khz of what’s specified, depending on frame encoding performance.
  Reviewed-by : Claudio Freire <klaussfreire@gmail.com>
  
  Signed-off-by : Michael Niedermayer <michaelni@gmx.at>
  

  • [DH] libavcodec/aaccoder.c
  • [DH] libavcodec/aacenc.c
  • [DH] libavcodec/aacenc.h

• How to run one script after another in Apple Script

  19 juillet 2015, par mskx4

  I’m trying with Apple Script to run three different scripts that would alow me to :

  1. Convert a purchased m4a file into an "anonymized" m4a file and extract its artwork (with ffmpeg)
  2. Attach the artwork to the file previously converted, since the converted file won’t maintain its artwork (with AtomicParsley)
  3. Remove the artwork from his path

  I don’t have any kind of programming knowledge, I’ve collected different script from the web and tried to make an app that could do these 3 simple task :

  on open argv
  
     set paths to ""
  
     repeat with f in argv
  
         set paths to paths & quoted form of POSIX path of f & " "
  
     end repeat
  
     tell application "Terminal"
  
          do script "for f in " & paths & "; do ffmpeg -i \"$f\" -acodec copy -y \"$f\" output.jpg; done"
  
          activate
  
          do script "for f in " & paths & "; do AtomicParsley \"$f\" --artwork output.jpg; done"
  
          activate
  
          do script "rm output. jpg"
  
          activate
  
     end tell
  
   end open

  The problem is that, when I drop a file on the app, it opens three terminal windows at once and it runs the three tasks in the same time, with the obvious result that the conversion fails : the first task overwrites the input file, and the second script should use the output of the first one as its input file. So I need the three scripts to be executed successively, one after another.

• avformat/asfdec_f : Parse ECC byte according to spec

  22 juillet 2015, par Michael Niedermayer

  avformat/asfdec_f : Parse ECC byte according to spec
  This should not change anything as the spec requires specific values
  
  for the fields, which where handled previously.
  Ask for samples when these values do not match
  Signed-off-by : Michael Niedermayer <michael@niedermayer.cc>
  

  • [DH] libavformat/asfdec_f.c